The difference between a hearing exam and a hearing (audiology) evaluation is subtle: the exam refers to a single test that makes up part of the overall evaluation. There are many different types of hearing exams that may be administered; these are discussed in detail in our Audiology Evaluations section.
Hearing exams are used to identify the presence of hearing loss, and measure the type, degree and configuration of the impairment.
Types of Hearing Loss
The type of hearing loss refers to which part of the hearing system has been damaged. Hearing loss is broken down into three basic types: conductive, sensorineural and mixed.
Conductive hearing loss occurs when there are problems in the outer or middle ear. This type of loss is usually mild to moderate, and can often be treated successfully with medication or surgery. There are many factors that can lead to conductive hearing loss, including excess fluid or earwax, ear infections, allergies, physical defects, foreign objects in the ear, swimmer’s ear, otosclerosis or benign tumors.
Sensorineural hearing loss results from damage to the cochlea and inner ear. It is often referred to as “nerve deafness” and is the most common type of hearing loss, responsible for about 90% of cases. Sensorineural hearing loss is incurable but can usually be treated successfully with hearing aids. Causes include aging, exposure to noise, trauma, viral infections, autoimmune disorders, ototoxic medications, diseases of the inner ear, genetic conditions and benign tumors.
Mixed hearing loss is a combination of both conductive and sensorineural hearing losses. Patients experience problems with the middle and outer, as well as the inner, ear. Treatment might include medications, surgery or hearing aids.
Degrees of Hearing Loss
The degree of hearing loss refers to its severity. Hearing loss is measured in decibels (dB) and ranges from normal to profound. It is classified as follows:
- Normal -10 to 15 dB
- Slight 16 to 25 dB
- Mild 26 to 40 dB
- Moderate 41 to 55 dB
- Moderately severe 56 to 70 dB
- Severe 71 to 90 dB
- Profound 91+ dB
Configurations of Hearing Loss
Hearing loss configuration refers to the pattern of loss across frequencies as charted on a patient’s audiogram. An individual whose loss affects the high tones is described as having high-frequency hearing loss; the configuration would show good hearing at lower pitches and poor hearing at higher pitches. Other types of hearing loss configurations include:
- Bilateral (hearing loss affects both ears) vs. unilateral (single-sided hearing loss)
- Symmetrical (hearing loss is similar in both ears) vs. asymmetrical (hearing loss can vary in degree and configuration in each ear)
- Progressive (a steady decline in hearing ability) vs. sudden (hearing loss occurs rapidly and without warning)
- Fluctuating (hearing loss changes over time; it may get worse or better) vs. stable (hearing loss remains the same)